the microscope

importance of the microscope in life science

Many life science discoveries would not have been possible without the microscope. For example: Cells are the tiny building blocks of living things. They couldnt be discovered until the microscope was invented. The discovery of cells led to the cell theory. This is one of the most important theories in life science. Bacteria are among the most numerous living things on the planet. They also cause many diseases. However, no one knew bacteria even existed until they could be seen with a microscope. The invention of the microscope allowed scientists to see cells, bacteria, and many other structures that are too small to be seen with the unaided eye. It gave them a direct view into the unseen world of the extremely tiny. You can get a glimpse of that world in Figure 1.10.

textbook_image

invention of the microscope

The microscope was invented more than four centuries ago. In the late 1500s, two Dutch eyeglass makers, Zacharias Jansen and his father Hans, built the first microscope. They put several magnifying lenses in a tube. They discovered that using more than one lens magnified objects more than a single lens. Their simple microscope could make small objects appear nine times bigger than they really were.

hooke discovers cells

In the mid-1600s, the English scientist Robert Hooke was one of the first scientists to observe living things with a microscope. He published the first book of microscopic studies, called Micrographia. It includes wonderful drawings of microscopic organisms and other objects. One of Hookes most important discoveries came when he viewed thin slices of cork under a microscope. Cork is made from the bark of a tree. When Hooke viewed it under a microscope, he saw many tiny compartments that he called cells. He made the drawing in Figure 1.11 to show what he observed. Hooke was the first person to observe the cells from a once-living organism.

van leeuwenhoek sees animalcules

In the late 1600s, Anton van Leeuwenhoek, a Dutch lens maker and scientist, started making much stronger microscopes. His microscopes could magnify objects as much as 270 times their actual size. Van Leeuwenhoek made many scientific discoveries using his microscopes. He was the first to see and describe bacteria. He observed them in a sample of plaque that he had scraped off his own teeth. He also saw yeast cells, human sperm cells, and the microscopic life teeming in a drop of pond water. He even saw blood cells circulating in tiny blood vessels called capillaries. The drawings in Figure 1.12 show some of tiny organisms and living cells that van Leeuwenhoek viewed with his microscopes. He called them animalcules.

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modern microscopes

These early microscopes used lenses to refract light and create magnified images. This type of microscope is called a light microscope. Light microscopes continued to improve and are still used today. The microscope you might use in science class is a light microscope. The most powerful light microscopes now available can make objects look up to 2000 times their actual size. You can learn how to use a light microscope by watching this short video: http MEDIA Click image to the left or use the URL below. URL: To see what you might observe with a light microscope, watch the following video. It shows some amazing creatures in a drop of stagnant water from an old boat. What do you think the creatures might be? Do they look like any of van Leeuwenhoeks animalcules in Figure 1.12? MEDIA Click image to the left or use the URL below. URL: For an object to be visible with a light microscope, it cant be smaller than the wavelength of visible light (about 550 nanometers). To view smaller objects, a different type of microscope, such as an electron microscope, must be used. Electron microscopes pass beams of electrons through or across an object. They can make a very clear image that is up to 2 million times bigger than the actual object. An electron microscope was used to make the image of the ant head in Figure 1.10.

textbook_image

instructional diagrams

description_image

The image below shows the different parts of an Optical microscope. The Optical microscope is a type of microscope which uses visible light and a system of lenses to magnify images of small samples. Optical microscopes are the oldest design of microscope and were possibly invented in their present compound form in the 17th century. Basic optical microscopes can be very simple, although there are many complex designs which aim to improve resolution and sample contrast. All modern optical microscopes designed for viewing samples by transmitted light share the same basic components of the light path. In addition, the vast majority of microscopes have the same 'structural' components. The eyepiece, or ocular lens, is a cylinder containing two or more lenses; its function is to bring the image into focus for the eye. The eyepiece is inserted into the top end of the body tube. Eyepieces are interchangeable and many eyepieces can be inserted with different degrees of magnification.

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This diagram shows the parts of a compound light microscope. The eyepiece is used to view a microscopic item placed on the stage. It can be used to view cells, bacteria, and small objects like insect wings. When holding a microscope, always use the arm and the base. Handle it carefully, as these are expensive and fragile objects. Use the condenser focus and objective lenses to make the object being viewed clearer. The course focus and fine focus can be used to adjust how close the lenses are to the stage. These focus pieces also make the image clearer.

description_image

The diagram shows the anatomy of a microscope. There are two optical systems in a compound microscope: The Ocular Lens and the Objective Lens. Eyepiece or Ocular is what you look through at the top of the microscope. Eyepiece Tube holds the eyepieces in place above the objective lens. Objective Lenses are the primary optical lenses on a microscope. They range from 4x-100x and typically, include, three, four or five on lens on most microscopes. Objectives can be forward or rear-facing. Nosepiece houses the objectives. The objectives are exposed and are mounted on a rotating turret so that different objectives can be conveniently selected. Coarse and Fine Focus knobs are used to focus the microscope. Stage is where the specimen to be viewed is placed. Stage Clips are used when there is no mechanical stage. Aperture is the hole in the stage through which the base (transmitted) light reaches the stage. Illuminator is the light source for a microscope, typically located in the base of the microscope. Condenser is used to collect and focus the light from the illuminator on to the specimen. Iris Diaphragm controls the amount of light reaching the specimen. It is located above the condenser and below the stage. Condenser Focus Knob moves the condenser up or down to control the lighting focus on the specimen.

questions

Who invented the microscope?

a. Robert Hooke

b. Anton van Leeuwenhoek

-->  c. Zacharias and Hans Jansen

d. none of the above

____The microscope was invented in the late 1800s.

a. true

-->  b. false

____The earliest microscopes were light microscopes.

-->  a. true

b. false

What is Micrographia?

a. a book published by van Leeuwenhoek

-->  b. the first book of microscopic studies

c. a method of drawing microscopic images

d. two of the above

To be seen with a light microscope, an object must be wider than 550

a. micrometers.

-->  b. nanometers.

c. millimeters.

d. centimeters.

____An individual bacterial cell is invisible without a microscope.

-->  a. true

b. false

____Many life science discoveries would not have been possible without the microscope.

-->  a. true

b. false

Electron microscopes can make clear images that are as much as two

a. hundred times bigger than the actual object.

b. thousand times bigger than the actual object.

-->  c. million times bigger than the actual object.

d. billion times bigger than the actual object.

____An electron microscope magnifies objects up to 2 billion times larger than their actual size.

a. true

-->  b. false

The tiny building blocks of organisms are called

a. bacteri

b. microorganisms.

c. animalcules.

-->  d. cells.

____The first microscope was made by Anton van Leeuwenhoek.

a. true

-->  b. false

____The Jansens discovered that one lens magnified objects more than several lenses.

a. true

-->  b. false

_The cell theory depended on the discovery of the microscope.

-->  a. true

b. false

_Only light of certain wavelengths is visible to the human eye.

-->  a. true

b. false

_The Jansens microscopes were stronger than van Leeuwenhoeks microscopes.

a. true

-->  b. false

_Electron microscopes are more powerful than light microscopes.

-->  a. true

b. false

_Light microscopes are no longer used today.

a. true

-->  b. false

____first scientist to observe bacteria with a microscope

a. microscope

-->  b. van Leeuwenhoek

c. cell

d. Jansen

e. electron microscope

f. Hooke

g. light microscope

____microscopic building block of all living things

a. microscope

b. van Leeuwenhoek

-->  c. cell

d. Jansen

e. electron microscope

f. Hooke

g. light microscope

____scientist who discovered cells

a. microscope

b. van Leeuwenhoek

c. cell

d. Jansen

e. electron microscope

-->  f. Hooke

g. light microscope

____type of microscope that uses lenses to refract visible light

a. microscope

b. van Leeuwenhoek

c. cell

d. Jansen

e. electron microscope

f. Hooke

-->  g. light microscope

____general term for an instrument that makes magnified images of very small objects

-->  a. microscope

b. van Leeuwenhoek

c. cell

d. Jansen

e. electron microscope

f. Hooke

g. light microscope

____name associated with the invention of the microscope

a. microscope

b. van Leeuwenhoek

c. cell

-->  d. Jansen

e. electron microscope

f. Hooke

g. light microscope

____type of microscope that passes electrons over or through objects

a. microscope

b. van Leeuwenhoek

c. cell

d. Jansen

-->  e. electron microscope

f. Hooke

g. light microscope

The invention of the microscope allowed scientists to see

a. cells

b. bacteria

c. human sperm

-->  d. all of the above

A microscope is an instrument that makes

-->  a. tiny objects look bigger

b. distant objects look closer

c. distant objects look bigger

d. large objects look smaller

The inventors of the microscope were

a. English

-->  b. Dutch

c. German

d. American

Van Leeuwenhoeks microscopes could magnify objects as much as

-->  a. 270 times their actual size

b. 550 times their actual size

c. 1,000 times their actual size

d. none of the above

Light microscopes refract visible light and form images with

a. electrons

-->  b. lenses

c. slides

d. bulbs

What is the magnification of the most powerful light microscope?

a. 20 times

b. 200 times

-->  c. 2,000 times

d. 2,000,000 times

The wavelength of visible light is

a. 5 nanometers

b. 55 nanometers

-->  c. 550 nanometers

d. 5,500 nanometers

diagram questions

question_image

Which label refers to the diopter?

a. P

b. W

c. H

-->  d. L

question_image

Which letter represents the eyepiece?

-->  a. W

b. H

c. P

d. L

question_image

Identify the base in this picture

-->  a. F

b. D

c. A

d. P

question_image

Which label shows the eyepiece?

a. T

b. J

c. D

-->  d. A

question_image

What is the purpose of letter A?

a. AS PROTECTION

b. TO ADJUST FOCUS

c. FOR MAGNIFICATION

-->  d. IT IS THE OCULAR LENS WHERE THE USER LOOKS INTO THE MICROSCOPE TO VIEW THE OBJECT BEING ANALYZED

question_image

What lets you look at the object?

a. H

-->  b. A

c. E

d. V

question_image

Which image shows the iris diaphragm?

-->  a. A

b. E

c. S

d. V

question_image

I use this structure to upper or lower the plate.

a. V

b. U

c. N

-->  d. E

question_image

What is below S?

-->  a. N

b. W

c. U

d. R

question_image

By what letter is the photo port represented in the diagram?

a. J

b. P

-->  c. E

d. W

question_image

Where is the frame?

-->  a. V

b. K

c. E

d. P

question_image

Which label shows the Condenser?

a. M

b. W

-->  c. N

d. J

question_image

Which label represents the head of the microscope?

-->  a. C

b. H

c. V

d. P

question_image

Which label shows the Ocular Lens?

-->  a. H

b. K

c. N

d. J

question_image

Where is the head of this microscope?

a. E

b. K

-->  c. C

d. M

question_image

Which part is used to focus the light onto the specimen?

a. E

b. N

-->  c. M

d. L

question_image

Where is the head located?

-->  a. C

b. H

c. P

d. V

question_image

Identify the internal light source in this picture

-->  a. F

b. M

c. K

d. R

question_image

Which letter represents the eyepieces?

-->  a. J

b. N

c. C

d. M

question_image

Which shows the stage of the microscope?

a. M

b. S

-->  c. V

d. J

question_image

Which label refers to the eyepiece?

-->  a. A

b. C

c. U

d. E

question_image

Which label shows the Arm?

-->  a. L

b. U

c. C

d. H

question_image

Identify the eyepiece in this microscope

-->  a. A

b. E

c. V

d. C

question_image

What part of the microscope do you think you put your eye up to?

-->  a. A

b. R

c. C

d. P

question_image

Identify the arm of this microscope

a. W

b. K

-->  c. A

d. C

question_image

Which letter represents the Lens?

a. W

b. K

-->  c. P

d. V

question_image

What part of a microscope is labelled V in this image?

a. STAGE

b. LENS

c. REVOLVING NOSEPIECE

-->  d. BODY TUBE

question_image

Identify J

a. OBJECTIVE LENS

b. FINE ADJUSTMENT

-->  c. OCULAR LENSES

d. STAGE

question_image

Which letter indicates the lenses that adjust viewing?

a. J

b. M

c. A

-->  d. K

question_image

What does J represent?

a. SLIDE HOLDER

b. LIGHT

c. LIGHT INTENSITY CONTROL

-->  d. OCULAR LENSES

question_image

Where would you put your eyes to view something through the microscope?

-->  a. J

b. P

c. C

d. A

question_image

Which label shows the Body Tube?

a. U

b. P

c. V

-->  d. R

question_image

Which structure regulates the light?

a. V

-->  b. F

c. N

d. W

question_image

Identify the high-power lens of the microscope:

-->  a. J

b. E

c. M

d. P

question_image

Identify the ocular lens in this microscope

a. N

b. S

c. W

-->  d. E

question_image

The lens is denoted by which letter in the picture?

-->  a. E

b. J

c. M

d. N

question_image

What does the 'Y' symbol indicate in the diagram?

a. COARSE FOCUS

-->  b. POWER SWITCH

c. FINE FOCUS

d. PROJECTION LENS

question_image

What's the name of the part used to look into the microscope?

a. Focus knob

b. Diopter

c. Stereo head

-->  d. Eyepiece

question_image

How many stage clips are there in a microscope?

-->  a. 2

b. 3

c. 1

d. 4

question_image

Which part of the microscope do you look into?

a. Diopter

b. Focus knob

-->  c. Eyepiece

d. Stereo head

question_image

How many parts does this microscope have?

a. 10

b. 7

-->  c. 8

d. 9

question_image

How many parts of the microscope are marked in the diagram?

a. 6

b. 7

-->  c. 8

d. 9

question_image

If the eyepiece is removed, what happens?

a. The user can still look through the stereo head as normal.

-->  b. The user will not be able to see the magnified object.

c. The user can still squint and use the microscope.

d. The user only needs to adjust the focus knob to use the microscope.

question_image

What should you adjust if your slide appears blurry?

a. stage plate

b. stereo head

-->  c. Focus knob

d. eyepiece

question_image

What of the microscope is labeled 1?

a. Base

-->  b. Eyepiece

c. Stage

d. Coarse Focus

question_image

What is the part used to see objects?

a. part 4

b. part 2

-->  c. part 1

d. part 3

question_image

Give the number of the part that connects the eyepiece to the objective lenses.

a. 10

b. 5

-->  c. 2

d. 3

question_image

How does the changing of objective lenses affect the image seen in the eyepiece?

a. The specimen is moved

b. The focus is changed

-->  c. The magnification is changed

d. The brightness is changed

question_image

How many parts are there in a microscope?

a. 15

b. 20

-->  c. 12

d. 13

question_image

What structure is located below the stage?

a. The objective power lens

b. The arm

-->  c. The diaphragm

d. The stage clips

question_image

What part do you look into?

a. arm

-->  b. eyepiece

c. stage

d. fine adjustment

question_image

What part of the microscope is where you look through?

a. Stage

b. Fine Adjustment

c. Objective Power Lens

-->  d. Eyepiece

question_image

How many eyepieces on a microscope?

a. 3

-->  b. 1

c. 2

d. 4

question_image

How many types of adjustment does the microscope have?

a. 1

b. 3

c. 5

-->  d. 2

question_image

Which part of the microscope do you look through?

a. Stage

b. Objective power lens

c. Stage clips

-->  d. Eyepiece

question_image

What is the bottom part called?

-->  a. base

b. tube or barrel

c. arm

d. eyepiece lens

question_image

What is the name of the piece that enables the user to adjust the amount of light that is focused?

-->  a. Diaphram

b. Coarse Focus Adjustment

c. Objective Lens

d. Light

question_image

What is the bottom of the microscope called?

a. Tube

b. Arm

-->  c. Base

d. Eyepiece Lens

question_image

What keeps the microscope from moving around?

a. barrel

-->  b. base

c. lens

d. eyepiece

question_image

How many parts is indicated in the diagram?

a. 15

b. 12

-->  c. 13

d. 14

question_image

How many types of lens are there in a microscope?

a. 1

-->  b. 2

c. 3

d. 4

question_image

What is the purpose or objective lens?

a. To allow light to pass through the stage

b. For balance

-->  c. The amount of zoom of the image

d. To hold the object

question_image

Which letter corresponds to the base?

a. C

b. D

c. A

-->  d. J

question_image

Which part provides light to the microscope?

a. B

b. D

c. A

-->  d. K

question_image

Which labels the eyepiece?

-->  a. A

b. D

c. F

d. C

question_image

How many parts of the microscope are there?

a. 10

b. 8

c. 9

-->  d. 11

question_image

What is the bottom part called?

-->  a. base

b. stage

c. nose piece

d. diopter adjustment

question_image

What is used to move the objective lenses toward or away from the specimen?

-->  a. Coarse focus

b. arm

c. base

d. fine focus

question_image

What connects the arm to the objective lens?

a. base

-->  b. nose piece

c. coarse focus

d. diopter adjustment

question_image

What part of the microscope do you place the object you are looking at?

a. Base

b. Arm

c. Eyepiece

-->  d. Stage

question_image

How many eyepieces does a microscope have?

a. 4

-->  b. 2

c. 3

d. 1

question_image

How many parts are there on the microscope?

a. 12

b. 15

c. 16

-->  d. 14

question_image

Which part of a microscope do you look through?

a. Nose piece

b. Focus

-->  c. Eyepiece.

d. Base

question_image

Which part of a microscope controls the amount of light going through the aperture?

a. variable intensity control

b. mirror

-->  c. iris diaphragm

d. illuminator

question_image

Which of the following could be used to adjust the image seen through the eyepiece?

-->  a. Fine focus

b. Arm

c. Iris diaphragm

d. Illuminator

question_image

How many focusing dials does this microscope have?

a. 3

b. 5

c. 1

-->  d. 2

question_image

How many types of lenses are used in the compound microscope as shown in diagram?

a. 3

b. 1

-->  c. 2

d. 4

question_image

What happens when fine focus is rotated?

a. The view in eyepiece is distorted

-->  b. The view in eyepiece improves

c. Fine focus can not rotate

d. No change in eyepiece view

question_image

Which part of the microscope is used to view the slide?

a. Arm

b. Mechanical Stage

c. Iris Diaphragm

-->  d. Eyepiece

question_image

What adjustable control is located on the front of the microscope's base?

a. Photo port

b. Nosepiece

c. Coarse and fine focus

-->  d. Light intensity control

question_image

What would one used to look at the magnified image by the microscope?

a. microscope objectives

b. frame

-->  c. eyepieces

d. condenser

question_image

What part of the microscope would one look into?

-->  a. Eyepiece

b. Tilting Head

c. Photo Port

d. Digital Camera

question_image

How many parts are there on this microscope?

a. 11

-->  b. 12

c. 13

d. 10

question_image

How many parts of the microscope are there?

-->  a. 12

b. 10

c. 11

d. 9

question_image

What is the part under the digital camera called?

a. frame

b. eyepieces

-->  c. photo port

d. nosepiece

question_image

What is the bottom part called?

a. head

b. ocular lens

c. nose piece

-->  d. base

question_image

What is the main microscope lens used to magnify tiny objects or examine minute specimens that are a part of larger objects that are otherwise invisible to the naked eye?

-->  a. Objective Lens

b. Diopter Adjustment

c. Mechanical Stage

d. Ocular Lens

question_image

The light switch controls what part of the microscope?

-->  a. Illumination

b. Ocular lens

c. Condenser

d. Objective lens

question_image

How many types of lens are there in a compound microscope?

a. 1

b. 4

c. 3

-->  d. 2

question_image

Who invented the microscope?

a.  Albert Van Helden

-->  b. Hans and Zacharias Jansen.

c. Robert Hooke

d. Anton van Leeuwenhoek

question_image

Where are the magnifying lenses of a microscope located?

-->  a. Body tube

b. Mechanical stage

c. Stage

d. Condenser

question_image

What is the wheel under the stage that adjusts the amount of light called?

a. fine control knob

-->  b. iris diaphragm

c. objectives

d. condenser

question_image

How many body tubes does the microscope have?

a. 3

b. 1

-->  c. 2

d. 4

question_image

How many eyepieces are there?

-->  a. 2

b. 1

c. 3

d. 4

question_image

What part of a microscope controls the focus?

-->  a. Fine control knob.

b. Arm

c. Objectives

d. Eyepiece.

question_image

What is the topmost part called?

a. arm

b. objective lenses

c. swiveling head

-->  d. eyepiece

question_image

From the diagram, identify the source of light for the microscope.

a. eye piece

-->  b. illuminator

c. fine focus

d. iris diaphragm

question_image

Where is the light source found in the microscope?

a. eyepiece

b. arm

-->  c. illuminator

d. lens

question_image

How many parts of the microscope are described in the diagram?

a. 13

b. 12

c. 9

-->  d. 11

question_image

What would happen if the microscope had no illuminator?

a. The eyepiece would stop working.

b. It would make the observation easier on the eyes.

-->  c. It would be impossible to observe the samples if they weren't illuminated properly.

d. It would make it impossible to use the focus.

question_image

It is the part of the microscope that connects the body tube and mechanical stage.

a. Mirror

-->  b. Arm

c. Base

d. Rack and Pinion substage

question_image

How many eyepieces does a microscope have?

a. 4

b. 8

-->  c. 1

d. 2

question_image

How many focusing mechanisms are present on the microscope?

-->  a. Two

b. Three

c. Five

d. One

question_image

What is the bottom part called?

a. arm

b. lens

-->  c. base

d. revolving nosepiece

question_image

What piece is also called the eye piece?

a. bodytube

-->  b. Lens

c. arm

d. objectives

question_image

Where would you look through this microscope?

a. Nose piece

b. Slide

-->  c. Ocular lenses

d. Stage

question_image

Which part of the microscope does the user look into?

a. Stage

b. Condenser

-->  c. Ocular lens

d. Objective lens

question_image

How do you look the objects on the stage?

a. With the slide holder

b. With the revolving nosepiece

c. With the carrying handle

-->  d. With the ocular lenses

question_image

How many ocular lenses does the microscope have?

-->  a. 2

b. 4

c. 3

d. 1

question_image

In the picture of a telescope below, what is closest to the eye when someone looks through the device?

a. Revolving Nosepiece

b. Carrying Handle

-->  c. Ocular Lenses

d. Condenser

question_image

What is the bottom part called?

-->  a. base

b. head

c. frame

d. nosepiece turret

question_image

In which part of the microscope do we put a glass slide with specimen?

a. Mechanical Stage Control

b. Base

c. Objectives

-->  d. Stand

question_image

What part do you look into on the microscope?

a. frame

b. eyetube piece

-->  c. ocular lens

d. head

question_image

What connects the head to the base in the diagram?

a. stand

-->  b. frame

c. objectives

d. eyepiece tube

question_image

How many parts are labeled on this microscope?

-->  a. 12

b. 5

c. 10

d. 15

question_image

Which part holds the slide?

a. Lens

b. Focus

c. Base

-->  d. Stand

question_image

Which structure/s holds a glass slide in place?

a. 13

b. 12

-->  c. 11

d. 10

question_image

What would one used to look at the magnified image by the microscope?

-->  a. 1

b. 3

c. 6

d. 7

question_image

Where on the diagram is the eyepiece of the microscope?

a. 7

b. 2

-->  c. 1

d. 3

question_image

Which number is the eyepiece?

a. 9

-->  b. 1

c. 2

d. 10

question_image

What structure holds the slide in place?

-->  a. Stage clip

b. Iris diaphragm

c. Arm

d. Body tube

question_image

What would one used to look at the magnified image by the microscope?

-->  a. ocular lens

b. body tube

c. revolving nosepiece

d. stage

question_image

How many lenses are depicted in the diagram?

-->  a. 5

b. 2

c. 6

d. 4

question_image

How many parts of the microscope are there?

a. 14

b. 12

-->  c. 16

d. 13

question_image

Which number corresponds to the base?

a. 6

b. 1

-->  c. 8

d. 4

question_image

Which number represents the eyepiece?

-->  a. 9

b. 10

c. 4

d. 1

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How many lenses labelled as 4 are present?

a. 4

b. 1

-->  c. 3

d. 2

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Which number corresponds to the arm?

a. 9

b. 2

c. 8

-->  d. 10

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Identify the stage

a. R

b. W

-->  c. X

d. L

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What part of a microscope holds your sample?

-->  a. mechanical stage

b. eyepiece

c. Objective lenses

d. arm

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What connects the lens to the objectives?

-->  a. body tube

b. Revolving nosepiece

c. stage

d. arm

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Identify the photo port

a. P

b. J

-->  c. E

d. H

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Identify the stage

a. R

b. V

-->  c. J

d. U

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Identify the arm

a. M

-->  b. S

c. U

d. F

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Identify the stage

a. W

b. K

c. F

-->  d. E

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Identify the stage

a. U

b. T

c. N

-->  d. C